N-(4-alpha,alpha-dimethylbenzylphenyl)-1-or-2-naphthylamines

ABSTRACT

WHERE R1, R9 AND R12 ARE PHENYL OR P-TOLYL GROUPS AND THE REMAINING R&#39;&#39;S, X AND Y MAY BE ALKYL OR VARIOUS OTHER SUBSTITUENTS, ARE USEFUL ANTIOXIDANTS FOR LUBRICATING OILS OR FOR VARIOUS POLYMERIC SUBSTRATES (E.G. POOLYPROPYLENE) ESPECIALLY IN COMBINATION WITH A DIALKYL THIODIPROPIONATE. TYPICAL ANTIOXIDANTS ARE 4,4&#39;&#39;-BIS-(ALPHA,ALPHA,-P-TRIMETHYLBENZYL)DIPHENYLAMINE MADE BY REACTING P,ALPHA-DIMETHYLSTYRENE WITH DIPHENYLAMINE,AND N-(4-ALPHA,ALPHA-DIMETHYLBENZYLPHENYL) - 1 - (ALPHA,ALPHA-DIMETHYLBENZYL)2-NAPHTHYLAMINE MADE BY REACTING ALPHA-METHYLSTYRENE WITH N-PHENYL-2-NAPHTHYLAMINE. R6, 1-((4-(R1-C(-R2)(-R3)-),2-Y-PHENYL)-NH-),2-X,4-(R5-   )PHENYL)-NH-)NAPHTHALENE   PHENYL)-NH-)NAPHTHALENE, 1-R15,2-((4-(R12-C(-R13)(-R14)-   PHENYL)-NH-),2-X,4-R8-BENZENE, 1-((4-(R9-C(-R10)(-R11)-)   C(-R4)(-R7)-)BENZENE, 1-((4-(R1-C(-R2)(-R3)-),2-Y-   (4-(R1-C(-R2)(-R3)PHENYL)-NH-(1,4-PHENYLENE)-C(-R4)(-R5)-   DERIVATIVES OF DIPHENYLAMINE OR PHENYLNAPHTHYLAMINE OF THE TYPES

United States Patent 3,781,361 N-(4-ALPHA,ALPHA-DIMETHYLBENZYLPHENYL)- 1- or -2-NAPHTHYLAMINES Edward L. Wheeler, Woodbury, Conn., assignor to Uniroyal, Inc., New York, NY.

No Drawing. Application Jan. 12, 1970, Ser. No. 2,382,

now Patent No. 3,666,716, which is a division of application Ser. No. 540,817, Apr. 7, 1966, now Patent No. 3,505,225. Divided and this application May 22, 1972, Ser. No. 255,495

Int. Cl'.C07c 87/28 U.S...CL 26091-570 R ,4 3 Claims '7 Aixsrn, A tcriojF THE DISCLOSURE Derivatives "of 'diphenylamine or phenylnaphthylamine 5 ?ty s.v

where R R and R are phenyl or p-tolyl groups and the remaining Rs, X and Y may be alkyl or various other substituents, are useful antioxidants for lubricating oils or for various polymeric substrates (e.g. polypropylene) especially in combination with a dialkyl thiodipropionate. Typical antioxidants are 4,4-bis-(alpha,alpha,-p-trimethylbenzyl)diphenylamine made by reacting p,alpha-dimethylstyrene with diphenylamine, and N-(4-alpha,alpha-dimethylbenzylphenyl) 1 (alpha,alpha-dimethylbenzyl)- Z-naphthylamine made by reacting:alpha-methylstyrene with N-phenyl-Z-naphthylamine. ,7 w v This application is a division of my copending application Ser. No. 2,382 filed Jan. 12, 1970 and now US. Pat. No. 3,666,716, which is in turn a division of my application Ser. No. 540,817, filed Apr,,7,,1966, now US. Pat. 3,505,225, issued Apr. 7, 1970. The subject matter disclosed herein is also disclosed in my application Ser. No. 787,577, filed Dec. 27, 1968, now US. Pat. 3,649,690, issued Mar. 14, 1972 which is in turn also a division of my aforesaid application Ser. No. 540,817. The subject matter disclosed herein is also disclosed in my copending applications Ser. No. 163,443, filed July 16, 197 1 and Ser. No. 164,144, filed July 19, 1971, which are divisions of my aforesaid application Ser. No. 787,577, which is in turn a division of my aforesaid application Ser. No. 540,817.

(III) 3,781,361 Patented Dec. 25, 1973 This invention relates to new antioxidants which are derivatives of diphenylamine and the phenylnaphthylamines, useful either alone, in combination with each other, or in combination with dialkyl 3,3'-thiodipropiomates, for the protection of organic materials having relatively low olefinic unsaturation, which are subject to oxidative deterioration, particularly at elevated temperatures. Examples of materials which are subject to oxidative deterioration at elevated temperatures either in the course of their processing or fulfilling their prescribed function and which are protected by the compounds of the invention are alpha-olefin polymers, polyamides, polyesters, polyacetals, acrylonitrile butadiene styrene thermoplastics, and lubricants of the petroleum oil type or of the synthetic type.

The compounds useful in the invention are represented by the Formulae I, II, III, IV or V, as follows:

R is a phenyl or p-tolyl radical,

R and R are methyl, phenyl or p-tolyl radicals,

R is a p-tolyl or neopentyl radical,

R is a methyl, phenyl, p-tolyl or 2-phenylisobutyl radical, R is a methyl radical;

B1 l l i H R3 where R is a methyl, phenyl, p-tolyl or 2-phenylisobutyl radical,

where Where R R R and R are as defined in Formula I,

R,, is a methyl, phenyl, p-tolyl or neopentyl radical,

R is a methyl, phenyl, or p-tolyl radical,

X is a methyl, ethyl, sec-alkyl containing from three to ten carbon atoms, alpha, alpha-dimethylbenzyl, alphamethylbenzyl, chlorine, bromine, carboxyl or metal car-- boxylate radical where the metal is zinc, cadmium, nickel, lead, tin, magnesium, or copper,

Y is a hydrogen, methyl, ethyl, sec-alkyl containing from three to ten carbon atoms, chlorine, or bromine radical;

X R1 RH N a.

I H 7 Ba 1 where R is a phenyl or p-tolyl radical,

R and R are methyl, phenyl or p-tolyl radicals,

R is a hydrogen, primary, secondary or tertiary alkyl containing from one to ten carbon atoms, or alkoxyl radical containing from one to ten carbon atoms which may be straight chain or branched,

X and Y are hydrogen, methyl, ethyl, sec-alkyl containing from three to ten carbon atoms, chlorine or bromine radicals;

V R H (I;

N I R 0 where R is a phenyl or p-tolyl radical,

R is a methyl, phenyl, p-tolyl or 2-phenylisobutyl radical,

R 5 a methyl, phenyl or p-tolyl radical; or

R12 Ru where R is a phenyl or p-tolyl radical,

R is a methyl, phenyl or p-tolyl radical,

R is a methyl, phenyl, p-tolyl or 2-phenylisobutyl radical,

R is a hydrogen, alpha,alpha-dimethylbenzyl, alphamethylbenzhydryl, triphenylmethyl or alpha,alpha ptrimethylbenzyl radical. Typical preferred chemicals useful in the invention are as follows:

Type IV:

R is phenyl and R and R are methyl. I

It has previously been known to employ 4,4-bis(1,1,3,3- tetramethylbutyl)diphenylamine as :an antioxidant for rubber.

U.S. Pat. #2,943,112 to Ivan C. Popoli et a1. describes the use of alpha-methylstyrene to reduce the amount of unreacted diphenylamine or monoalkylated diphenylamine present after alkylating the diphenylamine with the C5C12 Olefin- I U.S. Pat. #2,543,329 to C. S. Myers describes the stabilization of polyethylene with diphenylamine.

U.S. Pat. #2,519,755 to M. F. Gribbins describes the use of a dialkyl 3,3-thiodipropionate as a stabilizer for polyethylene.

U.S. Pat. #3,072,603 to C. E. Tholstrup describes the stabilization of poly-alpha-olefins by use of a stabilizer combination consisting of a diester of 3,3thiodipropionic acid and a nitrogen-containing compound of the following types:

H Q3 C wherein R and R are selected from the group consisting (a)----- PhenyL- yL. y p y y y of h dro en atoms and alk lradicals havin 1 to 12 car- (b).... p-Tolyl- MethyL. MethyL. p-Tolyl ..do.-. Do. y g y g bon atoms.

x Type II: R:

i--@ f R: R

R1 Ra Ra 4 5 1 X Y (1).... PhenyL. MethyL. MethyL. PhenyL. MethyL. MethyL. Alpha,a1pha-dimethylbenzyl. Hydrogen. 2) do do do do do do Bromo Bromo. (3) do do do do do..... Carboxyl Hydrogen. (4) do do do do do do Nickel carboxylate Do. (5 do do do do do do 2-butyl D (6; do do do do do do.... 2-oety1 Do. (7) ..d0-..... PhenyL. Phenyl- .do. PhenyL. PhenyL. Z-hexy Do.

Type III: Ra-I N R| 1 a Ra Ra X Y (1) Phenyl. MethyL Methyl Isopropoxy Hydrogen Hydrogen. (2) do do do Hydr 2-octyl- Do. (3) -.d0 Phenyl PhenyL. 2-hexyl Do.

The synthesis of 4-trityldiphenylamine and 4,4'-ditrityldiphenylamine has been reported by D. Craig]. Am. Chem- Soc. 71, 2250 (1949); G. Baum, W. L. Lehn', and C. Tamborskh']. Org. Chem. 29,1264 (1964) and also disclosed as a rubber antioxidant by A. W. Campbell US. Pat. 1,902,115 (Mar. 21, 1933) and U.S. Pat. 1,950,079 (Mar. 6, 1934), although the described structure was incorrect.

As indicated previously, the present derivatives of diphenylamine and phenylnaphthylamines are effective antioxidants for materials of low unsaturation. The materials of low unsaturation include essentially saturated polymers, whether resins or rubbers, such as the alphaolefin polymers including resinous homopolymers of alpha-olefins (e.g., polyethylene, polypropylene) or the rubbery copolymers of two or more different alpha-olefins (e.g., ethylene-propylene rubber, known as EPM). Also included are resinous or rubbery polymers having a minor amount of unsaturation, such as the alpha-olefin polymers which are rubbery terpolymers of two or more different alpha-olefins with at least one non-conjugated diolefin (e.g., rubbery terpolymers of ethylene, propylene, and dicyclopentadiene, 1,4-hexadiene, methylene norbornene, cyclooctadiene, or the like, known as EPDM); these ordinarily contain less than 25% of olefinic unsaturation (i.e., less than 25 by weight of the diolefin). Similarly, the acrylonitrile-butadiene-styrene polymers (called ABS thermoplastics) may be employed. These are usually either (1) graft copolymers of styrene and acrylo nitrile on a polybutadiene rubber spine or on a butadienestyrene rubber spine (with or without additional separately prepared styrene-acrylonitrile resin), or (2) physical mixtures of styrene-acrylonitrile resin with butadieneacrylonitrile rubber. The olefinic unsaturation (i.e., butadiene content) of such ABS compositions is frequently less than 40%. Other polymers useful in the invention include the polyamides (nylon), polyesters (e.g., polyethylene terephthalate or copolymers thereof, notably in the form of fibers or films), acetal resins (polymers or copolymers as described for example in Modern Plastics Encyclopedia, 1966, pages 109-113; see also US. Pat. 3,027,352). The present chemicals are useful also as antioxidants for lubricants, whether essentially natural lubricating oil obtained from petroleum, or synthetic lubricants of the type represented by such ester lubricants as alkyl esters of dicarboxylic acids (for example those in which the alkyl group has 6-18 carbon atoms and the dicarboxylic acid has 6-18 carbon atoms) or fatty acid (e.g., C -C acids) esters of polyols such as neopentyl glycol, trimethylol propane, pentaerythritol, or the like (see Synthetic Lubricants by Gunderson et al., Reinhold, 1962).

The present antioxidants are effective in theconventional amounts ordinarily used for protecting substrates from oxidation, usually within the range of from 0.01% to 4% by weight, based on the weight of the substrate.

The presently employed derivatives of diphenylamine and the phenylnaphthylamines are more elfective than the parent compounds or the known 4,4'-dialkyldiphenylamines either alone, in combinations, or in combination with dialkyl 3,3'-thiodipropionates (in which the alkyl groups typically contain from 8 to carbon atoms). The

relative proportions of the present chemicals and the di- The compounds of the invention such as shown in Formula -I may be prepared by alkylating the appropriate diphenylamine or phenylnaphthylamine with the appropriate olefin using a suitable acid catalyst such as aluminum chloride, zinc chloride, or acid clay. Where there are two groups of different structure on the diphenylamine nucleus a stepwise alkylation may be carried out. In the compounds which contained a trityl group, triphenyl- 'methyl chloride may be used as the alkylating agent.

The unsymmetrical diphenylamines may be prepared in two ways:

Since vinyl type olefins such as butene-l alkylate preferentially in the ortho position of diphenylamine and vinylidene type olefins such as alpha-methylstyrene and 2,4,4- trimethylpentene-l alkylate preferentially in the para position of diphenylamine, some of the described compounds can be prepared in one step by alkylating with mixtures of olefins, or by sequential alkylation using first one olefin then the other, without isolation of the intermediate.

Although the alkylation reactions occur primarily as described, in any preparation mixtures of ortho and para isomers as well as mono, di and tri alkylated products occur. Furthermore in alkylations such as the reaction of diphenylamine with octene-l some isomerization of the olefin occurs giving some 2-(alpha-ethylhexyl) diphenylmine as well as the predominant 2-(alpha-methylheptyl) diphenylamine. Since these isomers are difficult to separate, it is a preferred embodiment of the invention to use the reaction mixtures containing primary product and small amounts of the isomeric materials in preparing the antioxidants of the invention.

EXAMPLE I The preparation of 4-(1,1,3,3-tetramethylbutyl)- 4'-triphenylmethyldiphenylamine A mixture of 169 g. of diphenylamine and 30 g. of anhydrous aluminum chloride was heated to C. with stirring. 112 g. of diisobutylene was added dropwise over a one hour period. An exotherm occurred and the temperature was maintained at 115 C. during the addition. The mixture was heated at l35 C. for an additional hour, then cooled and poured into water. 400 ml. of benzene was added and the organic layer was separated, washed and dried. The benzene was removed by distillation and the residue product was fractionally distilled under reduced pressure. The fraction boiling at -175 C. (0.5 mm.) was the 4-(1,1,3,3-tetramethylbutyl)diphenylamine.

A mixture of 28.1 g. of 4-(1,1,3,3-tetramethylbutyl)diphenylamine, 27.9 g. of tn'phenylmethyl chloride, 5 00 ml. of acetic acid and 50 ml. of concentrated hydrochloric acid was heated under reflux. 25 ml. of acetic acid-water mixture was removed by distillation during the first hour, then the mixture was refluxed an additional 2 /2 hours. The reaction mixture was poured into Water and the resulting solid was removed by filtration. The solid was slurried with benzene and heated under reflux, then filtered hot to remove any insoluble material. The filtrate was evaporated to dryness and the crude product (27 g.) recrystallized three times from hexane, M.P. 203-205 C.

7 Analysis-Calculated for C H N (percent): C, 89.5; H, 7.84; N, 2.68. Found (percent): C, 89.7; H, 7.86; N, 2.85.

EXAMPLE II The preparation of 4,4'-bis(alpha,alpha, p-trimethyl benzyl) diphenylamine The preparation of 2,4,4-tris(alpha-dimethylbenzyl) diphenylamine A mixture of 85 g. of diphenylamine, 13.3 g. of anhydrous aluminum chloride, and 200 ml. of n-hexane was heated at the reflux temperature with stirring. 206 g. of alpha-methyl styrene was added dropwise during 1 /2 hours, and the mixture was stirred at 80-85 C. for 4 /2 hours. The reaction mixture was cooled and poured into water, the organic layer separated and washed three times with water, and the solvent was removed by distillation. The product was vacuum topped to 200 C. (0.5 mm.). Crystallization of the crude product (216 g.) from hexane removed most of the more insoluble 4,4'-bis(a.lpha,alphadirnethylbenzyl)diphenylamine. The filtrate was evaporated to dryness and the residue product (145 g.) recrystallized twice from isopropanol to obtain 49 g., M.P. 114-116 C. An analytical sample was prepared by chromatographing g. of the compound on 250 g. of alumina using benzene-80% hexane as the eluent. The first fractions obtained were evaporated and recrystallized twice from hexane, M.P. 121.5122.5 C.

Analysis.Calculated for C H N (percent): C, 89.5; H, 7.84; N, 2.68. M01 wt. 523. Found (percent): C, 89.5; H, 7.86; N, 2.63. M01 wt. 531.

EXAMPLE IV The preparation of 2,2'-dibromo-4,4'-bis(alpha,alphadimethylbenzyl) diphenylamine To a stirred solution of g of 4,4'-bis(alpha,alphadimethylbenzyl)diphenylamine in 300 ml. of glacial acetic acid was added 32 g. of bromine dissolved in 100 ml. of glacial acetic acid at room temperature. After the addition was complete the mixture was heated at 45 C. for ten minutes and the product was removed by filtration. The crude dibromo derivative was dissolved in benzene and the solution extracted with dilute sodium hydroxide, then washed with water. The benzene was evaporated and the product was recrystallized from isopropanol to obtain 39 g., M.P. 166167 C.

Analysis.Calculated for C I-I Br N (percent): C, 63.9; H, 5.15; N, 2.49; Br, 28.4. Found (percent): C, 63.5; H, 5.20; N, 2.77; Br, 28.1.

EXAMPLE V The preparation of 4,4' bis(alpha,alpha-dimethylbenzyl)-2-carboxydiphenylamine 187 g. of N-phenylanthranilic acid, prepared according to Org. Syn. Coll., Vol. II, p. 15, was dissolved in 500 ml. of a solution containing g. of potassium hydroxide. The insoluble material was removed by filtration. To the aqueous solution was added an aqueous solution containing 71 g. of zinc sulfate. The zinc N-phenylanthranilate was separated by filtration and dried.

A mixture of g. of zinc N-phenylanthranilate, 30 g. of zinc chloride and.500 ml. of 1,2-dichloroethane was heated under reflux with stirring. 118 g. of alpha-methyl styrene was added dropwise over a twenty minute period and the mixture heated under reflux for six hours. The reaction mixture was poured into water and chloroform added. The organic layer was separated and washed with dilute hydrochloric acid, then with water. The solvent was removed by distillation and the product recrystallized from isopropanol to obtain 88 g. of product, MP. 197- 199 C. Further recrystallization gave material which melted at 198-199 C. v

Analysis.--Calculated for C H NO (percent): C, 82.9; H, 6.90; N, 3.12. Found (percent): C, 83.0; H, 7.22; N, 3.32.

EXAMPLE VI The preparation of nickel 4,4'-bis(alpha,alphadimethylbenzyl)diphenylamine-Z-carboxylate 4.5 g. of 4,4'-bis(alpha,alpha-dimethylbenzyl)-2-carboxydiphenylamine was dissolved in 100 ml. of 0.01 N sodium hydroxide. 30 ml. of ethanol was added to aid solution and the solution was filtered to remove any undissolved material. 1.44 g, of nickel sulfate dissolved in 50 ml. of water was added to this solution with stirring and the resulting precipitated nickel salt was filtered and dried at 50 C.

EXAMPLE VII The preparation of 2-sec-butyl-4,4-bis(alpha,alphadimethylbenzyl)-diphenylamine A mixture of 169 g. of diphenylamine, 73 g. of butene-l and 25 g. of montmorillonite clay (Girdler Catalysts designation KSF/O) was heated for 5 hours at 175 C. in a one liter stirred autoclave. The catalyst was removed by filtration and the residue combined with a second reaction mixture obtained under similar reaction conditions. The crude mixture was purified by fractional distillation under reduced pressure. The fraction boiling at 136-137 C. (1.4 mm.) was 2-sec-butyldiphenylamine.

A mixture of 66 g. of 2-sec-butyldiphenylamine, 10 g. of montmorillonite clay (Girder Catalysts KSF/O), and 30 ml. of toluene was heated with stirring to 130 C. 76.5 g. of alpha-methylstyrene was added over a /2 hour period and the reaction temperature was maintained at 130-135 C. for five hours. The catalyst was removed by filtration, and the solvent was removed by distillation. The viscous residue product was fractionally distilled under reduced pressure. The fraction boiling at 240 C. (0.25 mm.) was the 2-sec-butyl-4,4'-bis(alpha,alpha-dimethylbenzyl diphenylamine.

Analysis.--Calculated for C H 9N (percent): C, 88.5; H, 8.46; N, 3.04. Found (percent): C, 88.6; H, 8.28; N, 2.87.

EXAMPLE VIII The preparation of 4,4'-bis(alpha,alpha-dimethylbenzyl)- 2- (alpha-methylheptyl) diphenylamine A mixture of 592 g. of diphenylamine, 471 g. of octene-l and 59 g. of montmorillonite clay (Girdler Catalysts designation KSF/O), previously dried at C.

for 3 hours, was heated at 175 C. for six hours in a 2-liter Magne-Dash autoclave. The catalyst was removed by filtration and the crude product subjected to fractional distillation. The fraction boiling at 150-170 C. (0.2 mm.) weighed 395 g. and assayed 85% Z-(alpha-methylheptyl) diphenylamine.

A mixture of 56 g. of Z-(alpha-methylheptyl)diphenylamine, 8.5 g. of montmorillonite clay (Girdler Catalysts designation KSF/O), previously dried at 120 C. for 16 hours, and 50 ml. of toluene was heated to C. with stirring. 52 g. of alpha-methylstyrene was added during a twenty minute period and the stirred mixture was maintained at 130 C. for four hours. The catalyst was removed by filtration and the crude product was fraction- 9 ally distilled under reduced pressure. The fraction distilling at 280 C. (0.5 mm.) wasthe desired product.

AnaIysis.-Calculated for C H N (percent): C, 88.2; H, 9.09; N, 2.71. Found (percent): C, 88.2; H, 9.05; N, 3.00.

- EXAMPLE IX The preparation of" 2-(alpha-methylpentyl)- 4,4'-ditrityldip henylamine A' mixture of 25.3 g. of 2-(alpha-methylpentyl)diphenylamine, 58.5 g. of trityl chloride, 2.5 g. of aluminum chloride and 50 ml. of benzene was heated under reflux for 3 /2 hours. 10 ml. of ethyl ether was added after cooling and themixture was then poured into water. The aqueous layer was removed and the organic layer was poured into an equal volume of hexane. The resulting precipitate, 7 8 g., was filtered. 'A.pure sample was obtained by chromatography on alumina using benzene as the eluent. followed by recrystallization from a 1:1 benzene-isopropanol mixture-The sample was dried under vacuum at 78? ,C. for 8 hours, M.P. 2205-2215 C.

Analysis,Calculated for C H N (percent): C, 91.2; H, 6.92, N, 1.90. Found (percent): C, 91.3; H, 7.38; N, 1.73.

EXAMPLE X The preparation of 4- alpha,alpha-dimethylbenzyl)- -4-isopropoxydiphenylamine IA mixture of 56.8 g. ofisopropoxydiphenylamine, 5 g. of anhydrous aluminum chloride and 100 ml. of n-hexane was heated at the reflux temperature with stirring. 30.7 g. of alpha-methylstyrene was added dropwise and after the addition was completed the mixture was heated an additional four hours at 70-75 C. The reaction mixture was poured into water and benzene was added to facilitate separation. The benzene layer was Washed with dilute sodium hydroxide, then water, and dried over sodium sulfate. The benzene was removed by distillation and the crude product was fractionally distilled. 51 g. of product s bt i e :iB.P. 211-216? (3.. (0.3 mm.).

Analysis-Calculated for C24H27N0 (percent): C, 83.4; H, 7.88; N, 4.05. Found (percent): C, 83.1; H, 8.35; N, 4.08.

' EXAMPLE XI The preparation of 2-(alpha-methylheptyl)-4'-(alpha,

-- alpha-dimethylbenzyl)diphenylamine H, 9.27; N, 3.51. Found (percent): C, 87.1; H, 9.22; N,

' EXAMPLE XH The preparation of 2-(alpha-methylpentyl)-4'-trityldi- H "pheii'yla'mine m A mixture of 846 g. of diphenylamine, 547 g. of hexene-l and 85" g. of montmorillonite-clay (Girdler Catalysts. designationKSF/O) was ..heated in a one gallon stirred autoclave for 6 hours at 225 C. The reaction mixture was diluted; with toluene and the catalyst rernoyedby filtration. Thesolvent and excess hexene-l were removed. ;bydistillation and, the crude. product was purified by fractional. distillation through a 10 inch column packedwith Berl saddles. The fraction boiling at 117-121" C. (0.1 mm.) was 2-(alpha-methylpentyl)diphenylamine.

A mixture of 50.6 g. of 2-(alpha-methylpentyl)diphenylamine, 27.9 g. of trityl chloride, 5 g. of anhydrous aluminum chloride and 150 ml. of benzene was heated at the reflux temperature for three hours. The reaction mixture was poured into water and the organic layer separated and washed four times with water. The solvent was removed by distillation and the unreacted starting material removed by distillation under reduced pressure, B.P. 123 C. (0.3 mm.). The residue product was chromatographed on alumina using 20% benzene-% hexane as the eluent. The product thus obtained was recrystallized twice from hexane to obtain the desired product: M.P. 67-71" C.

Analysis-Calculated for C37H37N (percent): C, 89.7; H, 7.48; N, 2.83. Found (percent): C, 89.8; H, 7.40; N, 3.07.

EXAMPLE XIII The preparation of N-(4-alpha,alpha-dimethylbenzylphenyl)-l-naphthylamine A mixture of 219 g. of N-phenyl-l-naphthylamine, 25 g. of montmorillonite clay (Girdler Catalysts designation KSF/O) and 300 ml. of toluene was heated to the reflux temperature and ml. of toluene was distilled from the mixture. The reaction mixture was maintained at C. and 260 g. of alpha-methylstyrene was added dropwise over a one hour period. The mixture was heated an additional four hours at C. The catalyst was removed by filtration and the product vacuum topped to 200 C. 1.0 mm.). The crude product was purified by chromatography on alumina using benzene-hexane mixtures as the eluent, followed by two recrystallizations from hexane. The pure product after drying under vacuum at 78 C. for six hours melted at 91.5-92.5 C.

Analysis.Calculated for C H N (percent): C, 89.0; H, 6.87; N, 4.15. Found (percent): C, 89.0; H, 7.06; N, 4.04.

EXAMPLE XIV The preparation of N-(4-alpha-alpha-dimethylbenzylphenyl) l (alpha-alpha-dimethylbenzyl) 2 naphthylamine A mixture of 219 g. of N-phenyl-2-naphthylamine, 30 g. of anhydrous aluminum chloride, and 250 ml. of benzene was heated with stirring to 70-75 C. 260 g. of alphamethylstyrene was added dropwise during a one hour period and the reaction mixture was maintained at 70-85 C. for four hours. The mixture was poured into water, more benzene was added and the benzene solution was was washed twice with water. The benzene was removed by distillation and the crude product vacuum topped at 200 C. (0.4 mm.). 394 g. of residue product was obtained. A pure product (M.P. 121.5-122.0 C.) was obtained by two recrystallizations from a benzene-hexane mixture.

Analysis.Calculated for C H N (percent): C, 89.6; H, 7.30; N, 3.08, mol. wt., 456. Found (percent): C, 89.8; H, 7.49; N, 3.12; mol. wt., 471.

EXAMPLE XV The preparation of N-(4-alpha,alpha-dimethylbenzylphenyl) -2-naphthylamine A mixture of 110 g. of N-phenyl-Z-naphthylamine, 12.5 g. of montmorillonite clay (Girdler Catalysts designation KSF/O) and ml. of toluene was heated at the reflux temperature with stirring. Water was removed from the catalyst by azeotropic distillation along with 100 ml. of

toluene. 65 g. of alpha-methylstyrene was added dropwise over a /2 hour period and the reaction mixture was maintained at 100 C. for two hours. The catalyst was removed by filtration and the solvent removed by distillation. The product was crystallized from hexane and after two recrystallizations from hexane melted at 92.092.5 C.

1 1 Analysis-Calculated for C H N (percent): C, 89.0; H, 6.87; N, 4.15. Found (percent): C, 88.6; H, 7.07; N, 3.85.

EXAMPLE XVI In this example the compounds of the invention were tested as stabilizers for polyacetal resins against thermal degradation.

The solid stabilizers were incorporated into unstabilized acetal copolymer resin based on trioxane (Celcon CKX- 205, see Modern Plastics Encyclopedia, 1966, p. 111, or US. Pat. 3,027,352), by dry blending for five minutes using a Waring blender. Liquid stabilizers were incorporated by dissolving in a suitable solvent, slurrying with the resin and steam under vacuum to remove the solvent. Five grams of the powdered resin containing 0.5% by weight of the stabilizer was placed in an open aluminum cup and exposed in a 230 C. oven for 45 minutes, and the loss in weight of the polymer was determined.

1 2 EXAMPLE XVIH This example demonstrates the usefulness of the compounds of the invention as stabilizers for synthetic lubricants of the ester type.

To 300 ml. of a synthetic lubricant, namely, di(2- ethylhexyl)sebacate (Plexol 201-1), is added 5.40 g. (2% by weight) of the antioxidant. The mixture is warmed and agitated to facilitate solution. When a homogeneous solution is obtained a 15 ml. sample is withdrawn and the neutralization value (ASTM D974-58T) is determined. The Saybolt viscosity is determined on a standard Saybolt viscometer. A 250 ml. sample is placed in a 750 ml. test tube with an open end formed as a ground glass joint. A copper washer and iron washer are polished with fine emery cloth, washed with acetone and placed on an air delivery tube having a lip to support the washers 6 mm. from the lower end of the tube which is beveled to allow free air flow. The air tube and washers are inserted in the test tube containing the oil sample to which an Allihn type ground glass joint con- TABLE I denser is connected. The assembly is placed in the well Compound: Percent Weight 1 5 of an aluminum heating block maintained at 400 F. The Control 31.9 flow of cooling water is started through the condenser r m t yl yl) trlphenyland a source of clean dry air is connected to the air tube methyldlphenylamine 0.84 and allowed to flow uninterrupted for 72 hours at a rate of N (4 alpha,alpha-dimethylbenzylphenyl)-2- 12,5 liters/hour.

naphthylamine 0.74 At the end of 72 hours the oil is allowed to come to N (4 alpha,alpha-dimethylbenzylphenyl)-1- room temperature and the oil loss determined. The oil naphthylamlne 0.86 sample is filtered, and the Saybolt viscosity, neutraliza- 4'4 butylidene b1s(6 tert.-butyl-metacresol) tion value (ASTM D974-58'I) and the amount of sludge (Santowhite Powder) 2.24 are determined.

TABLE III Viscosity at 210 F., Saybolt universal Neutralization seconds, afternumber, after- Oil lass Ohrs. 72 hrs. Ohrs. 72 hrs. 72 m Sludge 1) 4-(1,1,3,3-tetrameth lbut 1)4'-trit ldi h laml 3 (2) 2-(alpha-methylhep t zyl)E -bis(alghaglgli dimizliylbenzyl)diphenylaxnine.-- 3g 0 2g (3) 2-(alpha-methylheptyl)-4-(alpha,alpha-dimethylbenzyl) diphenylaminm. 38 39.5 0.16 22.6 6.9 Do. (4) N-(4-alpha,alpha-dimethylbenzylphenyD-l-naphthylamine 38 39.6 0.44 12.5 6.1 Medium (5) N-(4-alpha,alpha-dimethylbenzylphenyl)-2-naphthylamine 38 39.8 0.49 16.2 5.2 Heavy (6) N-(4-a1pha,alpha-dimethylbenzylphenyl)1(a1pha,alpha-dimethylbenzyl)-2- 38 39.8 0.29 14.0 5.2 Do.

naphthylamine. ControL. 38 43.2 0.25 32.2 5.2 Trace EXAMPLE XVII This example demonstrates the usefulness of the compounds of the invention as processing stabilizers for terpolymers composed of ethylene, propylene, and a small amount of a non-conjugated diene.

Two percent by weight of the stabilizer Was incorporated into unstabilized rubbery terpolymer, containing for example about 62% ethylene, 33% propylene and 5% dicyclopentadiene, on a mill at 150 F. and the mixture subjected to milling at 300 F. After various milling times the Mooney viscosity (ML-4 at 212 F.) of the polymer was measured. A rise in viscosity is indicative of degenerative cross-linking of the polymer due to heat and mechanical shearing.

EXAMPLE XIX This example demonstrates the usefulness of the compounds of the invention as stabilizers for polyethylene.

The stabilizers (0.1% by weight) were milled into unstabilized polyethylene (DYNH) at 310 F. for 5-7 minutes. The polymer was then extruded into plates, millimeters thick. The plates were aged at 375 F. and the time to resinification determined.

This example demonstrates the usefulness of the compounds of the invention as stabilizers for polypropylene in combination with dilauryl thiodipropionate. The stabilizers were incorporated into the polypropylene (unstabilized Profax 6501) by first milling the resin at 340 F. for several minutes, then adding the stabilizers to the polymer. The milling was continued for 8-10 minutes. The polymer was then molded into plates 90 millimeters thick. Three plates of each sample of stabilized polymer were aged at 300 F. in a circulating air oven. The break point was defined as the first sign of embrittlement or crumbling in two out of the three pieces.

Table V illustrates the synergism obtained with diphenylamine derivatives of the invention with dilauryl 3,3'-thiodipropionate both in stabilizaton and color and indicates their superiority over chemicals of prior art.

TABLE V Days to Conc., break at Initial Color at percent 300 F. color break 0.3 2 White..- Yellow.

Compound (1).... 4,4'-bis(1,1,3,3-tetramethylbutyDdiphenylainine.

(2). Dilauryl3,3-thiodipropionate. 0.4 10 -do... White.

4,4-bis(1,1,3,3 tetra- 0. l

methylbutyDdiphenylamine.

Dilauryl 3,3-thiodipropionate.

2,4,4-tris(alpha,alphadimethylbenzyDdiphenylamine.

Dilauryl 3,8-thiodipropionate.

4-(1,1,3,3-tetra.methylbutyl)-4-ttityldiphenylamine.

Dilauryl 3,3-thiodipropionate.

Nickel 4,4-bis(alpha,

alpha-dimethylbenzyl)diphenylamine2-carboxylate. Dilauryl 3,3'-thiodipropionate.

1 Prior art.

(3). 20 do Do.

(4)...- 30 .-.do Do.

(5).... 48 --.do Yellow.

0. 1 62 Off- Ofi-white.

white.

Table VI s a further illustration of the synergism between the diphenylamine derivatives of the invention and dilauryl 3,3-thiodipropionate.

Table VII illustrates the effectiveness of the phenylnaphthylamine derivatives of the invention as stabilizers for polypropylene, their synergism with dilauryl 3,3'-thio- 14 dipropionate and their superiority over chemicals of prior art.

TABLE VII Days to break Conc., at 300 Initial Color at Compound percent F. color break 0. 1 1 White.-. Yellow. (1) gg m 1 naphthyl' 0. 3 1 Bufi. Dark yellow.

0.3 1 Pink. Dark yellow.

(3)--- N-(4-alpha,alpha-dl- 0.1 2 White-.. Tan. methylbenzyl- 0.3 19 Tan Tan. phenyl)-1- naphthylamine.

(4).-- N-(4-alpha,alpha-di- 0.1 2 Ofi- Tan.

methylbenzyl white. phenyl)-2-naphthyl- 0. 3 16 Light Tan. amine. pink.

(5)- N-(4-alpha,alpha-di- 0. 1

methyl benzylhenyD-I-naph- 32 White..- Oflthylamine. white Dilanryl 3,3-thiodi- 0.4

propionate. (6).-. Ni lilhtlanyldm aph- 0. 1

y amine. Dilanryl3,3-thiodi- 0.4 12 white' propionate.

Dilauryl 3,8-thiodi- 0.4 white. white.

propionate.

(8)- N-(4-alpha,alpha.-di- 0. 1

irgethylgbgnzyli1 eny -na {mammm P 24 White-.- Do. Dilauryl 3,3-thlodi- 0. 4

propionate.

1 Prior art.

EXAMPLE XXI This example demonstrates the usefulness of the compounds of the invention in combination with dilauryl 3,3- thiodipropionate as thermal stabilizers for acrylonitrilebutadiene-styrene thermoplastics.

A 91.1% dispersion of a commercial ABS thermoplastic was made with chloroform as the dispersing agent. The ABS used in all studies contains approximately 56.5% styrene, 23.5% acrylonitrile, and 20.0% butadiene prepared by the method of Childers and Fisk, US. Pat. #2,820,773. Antioxidants were dissolved in chloroform and the proper amount added to the ABS homogerious dispersion.

Films were prepared on salt plates by evaporation of smears of the dispersions. The films were aged at 400 F. in a circulating air oven and the infrared spectrum examined at specified time intervals. The optical density of the 5.85 carbonyl band was plotted against time in minutes. The oxidative life of the polymer containing the antioxidants was defined by a large increase in the slope of the plot. Table VIII illustrates the effectiveness of the chemical combinations when compared to a commercial phenolic system.

15 16 I claim: References Cited 1. A chemical selected from the group consisting of UNITED STATES PATENTS -4-lh,lh-d' thlbnlh 1-1- hthl- N ap a y e Zyp any nap y 3,649,690 3/1972 Wheeler 260-57O amine and N-(4- 11pha,alpha-dimethylbenzylphenyl)-2-naphthyl- 5 ROBERT V HINES Primary Examiner amine.

2. N (4 alpha,alpha dimethylbenzylphenyl) 1- 252-401, 402; 26041.5 R, 45.75 R, 45.75 C K N,

naphthylamine. 45.85 45.9 R, 387, 388, 390 429 R, 429.7, 429.9, 435 R,

3. N (4 alpha,alpha dimethylbenzylphenyl) 2- 438.1. 439 R, 518 R A, 571, 576 naphthylamine. 10 

